1. The Field of the Invention
The present invention relates to systems and methods for controlling a consumer electronics device using a remote control device. More specifically, the present invention is directed to systems and methods for detecting and resolving interference between two infrared signals, wherein the first infrared signal is emitted from a remote control device to a first consumer electronics device and the second infrared signal is emitted from a signal relay device connected to the first consumer electronics device and sent to a second consumer electronics device.
2. The Prior State of the Art
Remote control devices for controlling functions on consumer electronics devices, such as televisions, have become widely accepted over the years. Remote control devices allow a viewer to change television channels, adjust volume, and control other features of the television without having to have to walk to the television set. As VCRs, cable boxes, and other components of home entertainment systems have proliferated, the value, number of features, and variety of remote control devices have increased.
With the increasing complexity of home entertainment systems, so called universal remote controls have been developed. Universal remote controls are capable of controlling functions of two or more consumer electronic devices. For example, many universal remote control devices can be used with televisions, VCRs, and cable boxes. In order to configure the universal remote control to be compatible with a particular type of VCR, for example, the user may enter an alphanumeric code to the remote control, thereby programming the remote control device to emit the appropriate signals for the particular make and model of the VCR.
Although universal remote controls have been quite popular, they have experienced some limitations. In particular, universal remote controls are typically self-contained devices containing code that is executed to select the particular infrared signal configurations compatible with selected consumer electronic devices. The code contained in the remote control device is generally not upgradable. Thus, when a user obtains a consumer electronic device not supported by the universal remote control there is typically no way of upgrading the remote control device short of purchasing a more sophisticated one. In addition, since remote control devices are typically battery-powered, including too many features and functions therein may cause the batteries to rapidly discharge.
FIG. 1 illustrates a remote control system that has been developed to allow a remote control device to be used with new consumer electronic devices and with electronics equipment produced by new manufacturers. The remote control system of FIG. 1 provides a degree of flexibility that has not been possible with simple universal remote control devices. One example of the remote control system of FIG. 1 is seen in WebTV set-top boxes (Internet terminals) manufactured by WebTV Networks, Inc., of Palo Alto, Calif. Internet terminal 10 is connected, by coaxial cable 12 or by another cable system to television 14. Remote control device 16 emits infrared signals 18, which are received at an infrared receiver (not shown) at Internet terminal 10. Infrared signals 18 may control selected functions at Internet terminal 10 and, optionally, at television 14. Another consumer electronics,device, which in this example is cable box 20, is connected to Internet terminal 10. Cable box 20 receives cable television programming via coaxial cable 22 and descrambles the cable television programming if necessary. The cable television programming signals may then be sent from cable box 20 to Internet terminal 10 and in turn to television 14 using coaxial cable 12 and 22, respectively.
In order for remote control device 16 to control cable box 20, information encoded in primary IR signals 18 is processed in Internet terminal 10 and sent from the Internet terminal to IR blaster 26 positioned near an IR receiver 28 at the cable box. Occasionally, infrared signals 18 emitted from remote control device 16 interfere with infrared signals 28 emitted from IR blaster 26. Such signal collision introduces the risk that cable box 20 will not execute the desired function. This risk is especially present when multiple signals are transmitted from remote control display 16 in rapid succession. For example, in order to tune to a selected television channel using cable box 20, a user may be required to enter three consecutive digits representing the channel number. It is possible that a signal 18 encoding the second digit may collide with a signal 18 encoding the first digit. In this situation, the user cannot be certain that cable box 20 has responded to the first digit because the cable box was simultaneously exposed again to the second digit emitted from remote control device.
In particular situations, such as that described above in reference to FIG. 1, IR signal interference and collision present a limitation in what is otherwise a very useful remote control system. The remote control system using infrared blaster 26 illustrated in FIG. 1 has the advantage of being readily updated to be compatible with consumer electronic devices produced by new manufacturers and with entirely new consumer electronic devices. In particular, the software in Internet terminal 10 for controlling the format, the speed, and other properties of the infrared signals 28 emitted from IR blaster 26 can be updated as needed.
In view of the foregoing, there is a need in the art for systems of resolving interference between two infrared signals in a remote control system. More specifically, it would be an advancement in the art to provide a system for reliably relaying signals to consumer electronic devices using infrared blasters so that multiple consumer electronic devices may be controlled by a single remote control device regardless of any infrared signal collisions.
The present invention is directed to systems and methods for detecting interference between two simultaneous infrared signals in a remote control system and for resolving such interference. According to the invention, information encoded in an infrared signal received from a remote control device is not relayed through an infrared blaster to a second consumer electronics device until the first consumer electronics device determines that no more signals are being sent from the remote control device. In this manner, the infrared blaster begins transmitting in the absence of competing signals from the remote control device. If the first consumer electronics device determines that an interfering signal is emitted from the remote control device while the IR blaster is transmitting information to the second consumer electronics device, the method of invention includes provisions for resolving this interference.
When the collision is detected after the IR blaster begins to transmit its signal, the IR blaster is caused to transmit a reset signal to the consumer electronics device. The reset signal places the second consumer electronics device at a known state in preparation for retransmitting the infrared signal. The reset signal may be any signal that causes the consumer electronics device to go to a known state. In one example, the reset signal is a channel up or channel down code that causes the consumer electronics device, such as a cable box, to be set to a selected television channel. This type of reset code is useful when the command that was being sent during the interference was a multi-digit number associated with a television channel.
Once the reset signal has been received at the consumer electronics device, the Internet terminal and the IR blaster retransmit information that was lost at the consumer electronics device by the reset signal and the information encoded in the infrared signal. For example, if the command that was interfered with was a multi-digit code associated with the television channel, the Internet terminal and the IR blaster retransmit the previously sent digits of the television channel. This technique places the consumer electronics device in the condition that it would have been in had there been no interference from signals emitted by the remote control device.
The systems and methods of the invention allow remote control systems having IR blasters to reliably control television channels and other functions of consumer electronic devices regardless of the occurrence of the interference between signals emitted from the IR blaster and signals emitted from the remote control device. Moreover, the invention enables the use of a single IR blaster configured to transmit signals to multiple consumer electronics devices associated with an Internet terminal or another central electronics device. In the absence of the techniques for detecting and resolving IR signal interference disclosed herein, the use of single IR blaster to control multiple devices could relatively frequently subject the multiple consumer electronics devices to the problems traditionally associated with IR signal interference. However, the methods and systems of the invention essentially eliminate the problems that have been previously experienced. The use of a single IR blaster in a home entertainment system can significantly reduce the cost and the complexity of home entertainment systems that include a large number of interconnected consumer electronics devices.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.